Stretching nearly halfway across the sun, the looping eruption of ionized helium "is definitely one of the largest" solar prominences ever witnessed, said Madhulika Guhathakurta, a STEREO program scientist at NASA headquarters in Washington, D.C.

The looping, gaseous eruptions are linked to changes in the strength of the sun's magnetic field, though the details of how solar prominences form remain an active area of research, Guhathakurta said.

Often when a prominence is rising above the surface of the sun, the magnetic field becomes so stressed that the gaseous loop "actually erupts, opens up," creating what's known as a coronal mass ejection, expelling "a huge amount of material into space," she said.

Coronal mass ejections can send bursts of charged particles, called solar wind, streaming toward Earth, where they can overload our planet's magnetic shield, knocking out satellite communications and power grids.